IAN Murray was marked down as "negative" on Jeremy Corbyn's little lists of enemies within that leadership aides drew up this Spring.

The Shadow Scottish Secretary, and Scotland's only Labour MP, was mildly surprised to say the least. He'd only spent the previous seven months publicly defending the new leader.

But just how "negative" Ian Murray is, and how long that list of enemies is, Jeremy Corbyn is about to discover.

The labour leader has been accused of being half hearted in the Brexit debate (Image: REUTERS/Peter Nicholls)

Murray is Labour's Scottish unicorn, there is only one Scottish Labour MP and while other Shadow cabinet vacancies can be filled, Murray is irreplaceable. There is no one who can credibly take his place

Murray is expected to be one up to seventeen members of the Labour shadow cabinet to have resigned their post by the end of today. That would leave Corbyn encircled with perhaps 12 loyalist shadow cabinet members at his back

Since having his own jotters marked Murray has had no hesitation in telling Corbyn he is a liability as Labour leader. The Edinburgh South MP was one of several shadow cabinet members to speak out against Corbyn during the shadow cabinet meeting in the post-Brexit rubble last Friday.

The leader must have sensed the move against him then because the mounting coup was sprung early by Corbyn himself. He called Hilary Benn in the early hours of Sunday morning having read that the Shadow Foreign Secretary was on maneouveres against him.

Benn was sacked on the phone in the middle of the night and in dawn's light Heidi Alexander, the shadow Health Secretary, resigned with "heavy heart".

We don't hear much about Heidi Alexander in Scotland as health is a devolved policy area. But she was instrumental in making the government blink in its dispute with the junior doctors in England.

When she introduced Corbyn at the staged show of unity at the TUC HQ during the referendum campaign she gave a rousing stump speech which marked her out for bigger things.

Others will turn their fire on Corbyn during the day. Ivan Lewis, Labour MP and candidate for Manchester mayor, has called on him to resign.

Heidi Alexander has resigned this morning (Image: Twitter)

Gloria del Pierro has just announced her resignation as Shadow Minister for Women and Equalities. That is significant, she is a close ally of deputy leader Tom Watson who is rushing back to London.

John McDonnell has insisted that Cotbyn "is going nowhere". If there is a leadership campaign Corby would stand again and McDonnell would chair his campaign, having ruled himself out as a runner.

The shadow cabinet were planning to confront Corbyn on Monday which is maybe why this morning's events found deputy leader Tom Watson caught out dad-dancing at Glastonbury and desperately trying to get a train back to London this morning.

Jeremy Corbyn has pledged to fight for his job (Image: Reuters)

As his train passes each station stop, the list of Labour MPs speaking out against Corbyn grows longer.

Watson will be instrumental in telling Corbyn that the game is up. The resignation of the irreplaceable Murray will be the sign to Corbyn that he cannot go on.